Wednesday, January 16, 2008

Zetia: Just the Latest Chapter in Hiding Data

There have been many interesting posts written about how data regarding Zetia were buried for quite some time. One of the main storylines in this saga is that it took about two years after the study was completed to analyze and release the data. The most disappointing aspect of this story is that few if any outlets are noting that this is not a fluke event.

Clinical trials are a huge part of how drugs are marketed. After examining clinical trial data, physicians who prescribe their drug believe they are engaging in evidence-based medicine. Granted, most physicians have little training in actually understanding statistics or research design, which are key in understanding clinical trial evidence. But that's not the point of this post...

The point is that Zetia is just the latest chapter in a lengthy volume of hidden clinical trial data. Here's one study in which it appears that data were reported on 1 of 15 participants. There was also a study examining Zoloft for PTSD in which data were reported about 10 years after the end of the study. How about suicide attempts apparently vanishing from a study report on Prozac? And a 5-6 year delay in reporting results on Effexor for depression in youth?

The above reports on hiding data were all based on studies I encountered randomly. I did not go fishing to find studies which published their data many years after it was collected or only reported a partial picture of their results. I was just looking through journals and happened to run across the studies mentioned above. Publication bias does not just occur when negative results are simply not published (which seems a fairly common practice), but it also occurs when negative results are published after a long delay. Delaying negative data means raking in more cash before the negative data reduces prescriptions for a product.

So you can be outraged by the Zetia story if you'd like, but please don't act surprised. Similar events will happen again and again and again.

Update: Welcome to those of you who have clicked the link from the Wall Street Journal. Please take a look around to find a series of documented incidents where science has been overrun by marketing. Add comments as you deem appropriate.

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